This invention relates to a recording system for performing recording with a recording member in the form of an endless belt which is supported and driven by a plurality of rollers.
In the recording system of the aforesaid construction, the recording member of the endless belt form is driven by the rollers. During operation, the recording member might be shifted in a direction at right angles to the direction in which it is driven or it might be deflected from its normal direction of movement or move in a zigzag manner with respect to its normal direction of movement due to some errors occurring in the tension imparted to the endless belt recording member by the rollers or errors occurring in the parallelism of the roller axes which should essentially be genuinely parallel. When this phenomenon occurs, the image formed on the recording member or the image formed on the recording sheet by transfer printing might be distorted. Thus this phenomenon should be avoided.
To this end, the following devices are known in the prior art. In one device known in the art, the rollers for supporting and driving the recording member of the endless belt are each formed with a flange for preventing deflection of ends of the recording member to avoid zigzagging or displacements of the recording member. In another device, at least one of the rollers for supporting and driving the endless belt recording member is provided with automatic self-aligning means operative to vary the inclination of its automatic self-aligning shaft contained therein to cause the belt to shift in a direction opposite the direction in which the belt is displaced or deviates by utilizing the force produced by the deviation of the belt. In the former device, stress is produced at all times in the end portion of the recording member of the endless belt by the force produced by the deviation of the recording member. The stress thus produced causes deformation of the end portion of the recording member of the endless belt, thereby greatly reducing the service life of the belt and reliability of the recording system. Thus to use this recording system requires either an increase in the thickness of the base of the recording member to increase the resistance offered by the belt itself to the deformation of its end portion or a reduction in the force produced by the deviation of the belt. When the base of the recording member of the endless belt has its thickness increased, however, problems are raised with regard to a reduction in the strength with which the recording layer attached to the base is maintained in intimate contact therewith and an increase in the tension of the belt due to an increase in bending stress. Thus an increase in the thickness of the base of the belt is not desirable. When an attempt is made to reduce the force with which the belt deviates, it is necessary to effect fine adjustments of the belt tension, and this inevitably makes the recording system high in precision finish and complex in construction. Meanwhile, the automatic self-aligning means could not operate satisfactorily unless there is provided rollers of high precision finishes. This would make the system complex in construction, large in size and high in cost.